1. Field of the Invention
This invention relates to a solar system for a vehicle, especially a motor vehicle, which has a solar generator and an energy storage for supplying power to at least one power consuming device, the solar generator being intended for charging of the energy storage.
2. Description of Related Art
Generic solar systems (see, for example, German Patent DE 41 30 226 C1 corresponding U.S. Pat. No. 5,259,814) ordinarily comprise a solar generator on the motor vehicle roof, for example integrated into an adjustable cover, the generated electrical power of which is used to charge the motor vehicle battery which is usually a 12 V lead storage battery, and to operate the motor of a fan which can ventilate the vehicle interior while the vehicle is standing still and thus can especially control the climate much more favorably in the case of strong incident solar radiation. Providing a control device which can, for example, prevent the auxiliary fan motor from discharging the motor vehicle battery is known.
The auxiliary fan is often operated depending on the incident solar radiation. This can often result in operation of the fan motor for a long time at an unfavorable operating point. This results in low hydraulic efficiency and also a reduction of the service life due to increased bearing wear (the lubricating film only builds up at several hundred rpm) and furthermore results in the deposition of paste-like abraded carbon particles on the collector when an electric motor with brushes is used. In this design, the service life of the motor in solar operation is problematic. Brushless fan motors, however, require relatively high minimum voltages for their operation, ideally the vehicle electrical system voltage, and a relatively high minimum power supply.
The primary object of this invention is to devise a solar system for a motor vehicle which enables more flexible and thus more efficient operation of a power consuming device supplied by the solar generator or the energy storage and thus offers relative high discharge safety of the energy storage.
This object is achieved by a solar system for a motor vehicle with a solar generator and an energy storage for supplying power to at least one power consuming device, where the solar generator charges the energy storage, and where the energy storage is at least one high-capacitance capacitor. Here, it is advantageous to use a capacitive energy storage with high capacitance in interaction with a solar generator. On the one hand, higher and more variable operating voltages are possible since one such energy storage is much more resistant to markedly cyclic operation than the conventionally used 12 V lead storage batteries. On the other hand, the inherently smaller energy storage capacity compared to conventional lead storage batteries, especially the high self-discharge during longer stationary periods, can be balanced by means of the charging option via the solar generator. In addition, the solar generator during the operating periods of the motor vehicle offers support of the capacitive energy storage so that, especially at a high solar output, it is also possible to save fuel.
In the following, the invention is described in greater detail with reference to the accompanying drawings.